SUSCEPTIBILITY OF MONOCLONAL IGG PARAPROTEINS TO PLASMIC CLEAVAGE USING GLYCERIN STABILIZED HUMAN PLASMIN

To shed further light on plasmin-IgG interactions a simple procedure is described that permitted 48 monoclonal IgG isolates from human serum to be profiled for their susceptibility to plasmic cleavage. In addition to anodal Fc and cathodal Fab fragments, combined immunoelectrophoresis electrophoresis revealed transient anodal banding, as well as Fab-fragment subcleavage in many of the IgG subclass-1 isolates. The subcleavage of released Fab fragments, which bear the idiotype determinants, points to a possible ancillary role of plasmin in ''idiotype processing'' leading to immunoregulatory antiidiotype networks. The cleavage of IgG by endogenous plasmin also points to a possible active role of plasmin in the ''steady-state'' metabolism of IgG. (C) 1994 Academic Press, Inc.